1. Field of the Invention
The present invention relates to a projection-type image display device including units for cooling light sources.
2. Description of the Related Art
A projection-type image display device uses a halogen lamp as a light source, and is configured to modulate lights emitted from the light source using a light valve such as a liquid crystal panel and configured to project the resultant light. Accordingly, a projection-type image display device needs to have a light source with high luminance. However, there has been a drawback that heat generated by the light source with high luminance causes a reduction in the luminescence property of the light source and a decrease in the lifetime thereof.
For this reason, conventionally, cooling air generated by a fan is blown to the light source to cool the light source, and then the air heated inside a housing of the device is A discharged to the outside of the housing (see Japanese Patent Application Laid-open Publication No. 2001-222065).
On the other hand, development has been pursued on a projection-type image display device using a solid-state light source such as an LED (light-emitting device) and an LD (laser diode) in place of a halogen lamp as a light source. In this type of projection-type image display device, the temperature range for allowing the solid-state light source to efficiently emit light is low. More specifically, the light-emitting operation must be performed at a temperature of about 100° C. or less. For this reason, this type of projection-type image display device requires stricter measures against the heat issues as mentioned above than the conventional lamp-type light source.